msm: mdss: Synchronize control stop and ESD check

Use ctl mutex offlock to synchronize between control
stop and BTA ESD status check function to prevent any
race condition.

Change-Id: I841e03a066b6e9e193ba9c6deae20d5527d4a20f
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>